Answer and Discussion of Quiz Set: N-009

5.    Polysaccharide that cannot be digested by diastase is the major constituent of the abnormal accumulation of which of the following diseases?

A.  Adult polyglucosan body disease

B.  McArdle's disease

C.  Farber's disease

D.  Gauche's disease

E.  Dementia with Lewy bodies

Answer and Discussion: The answer is (A). Adult polyglucosan body is a rare disease. The salient features are severe weakness, motor and sensory loss, ataxia, incontinence, and dementia. Seizure may be seen at the early stage before dementia becomes a prominent component. Histologically, it is characterized by substantial number of polyglucosan bodies throughout the nervous system and in other organs. Polyglucosan bodies are very similar to corpora amylacea. It is composed of polysaccharides, strongly positive with PAS stain, and cannot be digested by diastase. The accumulation in McArdle's disease is normal glycogen and can be digested by diastase. The accumulation in Farber's disease and Gauche's disease are both lipids. The abnormal inclusion bodies in dementia with Lewy bodies, both pale bodies and Lewy bodies, are composed of alpha-synuclein but not polysaccharides.

Reference:

Cavanagh JB. Corpora-amylacea and the family of polyglucosan diseases. Brain Res Brain Res Rev. 1999 Apr;29(2-3):265-95.